Scaling a Soft Body object
Unless you're using the soft body 'goal', changes to the original mesh will not affect the soft body simulation. Many of the other potentially useful parameters (such as Edge Length) are 'locked in' at the start of the simulation and changes similarly do not affect the simulation.

However, one way of achieving the desired effect is to use the Self Collision settings to exert a force within each 'bubble' to push it outwards, causing it to expand.

To achieve this, enable Self Collision and set the Ball Size to a suitably high value. This will simulate a collision ball around each vertex of the specified size, pushing each other vertex away. Set the Stiffness to a low value - this is the 'force' that each vertex is pushed away from its close neighbors. Reduce the Edge Pull to remove any force opposing the Self Collision 'push' and increase the Bending spring if necessary to prevent the bubble from collapsing. You should now find that each bubble expands to fit the available space.

Don't forget to add Collision to each bubble to prevent it from intersecting with the other bubbles and also set the Error Limit to a small value to improve the simulation.



This can produce the following result :